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New Member

transfer BPDUs between two ports.

Hi all,

i have Catalyst 3750.

i want to configure two ports as trunk, which connected to aggrigation ring.

i want those trunks to be able recive all tagged vlans and also transfer MSTP BPDUs between them, without been MSTP member.

i tried configuring those ports with:

switch port mode dot.q tunnel

l2tp tunnel stp

i dont want to use QinQ tunneling.

the BPDUs were transfer OK between the two ports but the Tagged vlans wasn't.

i attached the scenario to make it more clear.

any ideas?

thanks,

alon.

6 REPLIES
Hall of Fame Super Silver

Re: transfer BPDUs between two ports.

Hello Alon,

>> the BPDUs were transfer OK between the two ports but the Tagged vlans wasn't.

This should mean ports connected to 802.1Q tunnels are not trunking.

configure switch1 and switch4 ports connected to tunnels as trunks unconditionally

int gx/y

switchport

switchport trunk enc dot1q

switchport mode trunk

switchport nonegotiate

Hope to help

Giuseppe

New Member

Re: transfer BPDUs between two ports.

Thanks for your response,

but i think you got me wrong.

first, switch1 ans switch4 are not CISCO's switchs.

the trunks works fine between cisco and my switches, i just want to tunnle the BPDUs between the two Cisco's ring port without interrupting the Trunk fanctionality.

i hope it's more clear now,

please advice,

Thanks,

alon

Hall of Fame Super Silver

Re: transfer BPDUs between two ports.

Hello Alon,

sorry for my misunderstanding you need to use L2 protocol tunneling on the 802.1Q tunnel ports of C3750:

l2protocol-tunnel [cdp | stp | vtp]

see

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_46_se/configuration/guide/swtunnel.html#wp1010798

by default 802.1Q tunneling in Cisco implementation does not propagate BPDUs so you need to enable it explicitly.

Hope to help

Giuseppe

New Member

Re: transfer BPDUs between two ports.

Thanks, but how can i Combine 802.1q trunk with STP-BPDU tunnel?

Hall of Fame Super Silver

Re: transfer BPDUs between two ports.

Hello Alon,

>> how can i Combine 802.1q trunk with STP-BPDU tunnel?

the 802.1Q tunnel carries tagged frames by default the commands for L2 protocol tunneling add transport of BPDUs they are not an alternative to tagged frames transport service.

Hope to help

Giuseppe

New Member

Re: transfer BPDUs between two ports.

thanks, but i dont want to divide this network to CVLAN and SVLAN. i want that Vlan 100 on Switch-3 will be able to comunicate with Vlan 100 on the Catalyst.

Please advise,

Thanks,

Alon.

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